Detection of dysplasia and carcinoma in situ with a lung imaging fluorescence endoscope device

Clinical Practice of Photodynamic Therapy for Non-Small Cell Lung Cancer in Different Scenarios: Who Is the Better Candidate?

BACKGROUND

Photodynamic therapy (PDT) is a relatively safe and highly selectivity antitumor treatment, which might be increasingly used as a supplement to conventional therapies. A clinical overview and detailed comparison of how to select patients and lesions for PDT in different scenarios are urgently needed to provide a basis for clinical treatment.

SUMMARY

This review demonstrates the highlights and obstacles of applying PDT for lung cancer and underlines points worth considering when planning to initiate PDT. The aim was to make out the appropriate selection and help PDT develop efficacy and precision through a better understanding of its clinical use.

KEY MESSAGES

Increasing evidence supports the feasibility and safety of PDT in the treatment of non-small cell lung cancer. It is important to recognize the factors that influence the efficacy of PDT to develop individualized management strategies and implement well-designed procedures. These important issues should be worth considering in the present and further research.

Pulmonary squamous cell carcinoma and lymphoepithelial carcinoma - morphology, molecular characteristics and differential diagnosis

Squamous cell carcinoma (SCC) comprises one of the major groups of non-small-cell carcinoma of the lung, and is subtyped into keratinising, non-keratinising and basaloid SCC. SCC can readily be diagnosed using histomorphology alone in keratinising SCC. Confirmatory immunohistochemical analyses should always be applied in non-keratinising and basaloid tumours to exclude differential diagnoses, most prominently adenocarcinoma and high-grade neuroendocrine carcinoma, which may have important therapeutic consequences. According to the World Health Organisation (WHO) classification 2015, the diagnosis of SCC can be rendered in resections of morphologically ambiguous tumours with squamous immunophenotype. In biopsies and cytology preparations in the same setting the current guidelines propose a diagnosis of 'non-small-cell carcinoma, favour SCC' in TTF1-negative and p40-positive tumours to acknowledge a possible sampling bias and restrict extended immunohistochemical evaluation in order to preserve tissue for molecular testing. Most SCC feature a molecular 'tobacco-smoke signature' with enrichment in GG > TT mutations, in line with the strong epidemiological association of SCC with smoking. Targetable mutations are extremely rare but they do occur, in particular in younger and non- or light-smoking patients, warranting molecular investigations. Lymphoepithelial carcinoma (LEC) is a poorly differentiated SCC with a syncytial growth pattern and a usually prominent lymphoplasmacytic infiltrate and frequent Epstein-Barr virus (EBV) association. In this review, we describe the morphological and molecular characteristics of SCC and LEC and discuss the most pertinent differential diagnoses.

Role of I-scan technique in screening for lung cancer in smokers with positive sputum cytology

Background

Lung cancer has a very poor prognosis and high mortality. Positive sputum for malignant and/or atypical cells warrants the need for fibreoptic bronchoscopy. White light bronchoscopy (WLB) is usually unable to detect preinvasive lesions; therefore, autofluorescence bronchoscopy (AFB) was introduced as a gold standard for detecting such lesions. The aim of this work was to investigate the role of I-scan as a screening tool for cancer in smoker patients showing positive sputum cytology.

Results

New suspicious findings under I-scan occurred in 11 patients (36.7%). The overall sensitivity of WLB alone to diagnose malignancy is 23.3%, in contrast to an added sensitivity of 50% when I-scan was combined with white light (p value < 0.05). The specificity of I-scan could not be assessed in the absence of control cases (true negatives). No major complications or deaths occurred. Haemorrhage and bronchospasm were the commonest minor complications.

Conclusions

The addition of I-scan to the routine white light examination can increase the overall sensitivity of bronchoscopic screening in cases of sputum suspicious for malignancy if put in experienced hand. The suggested increase in procedure duration due to the combined use of I-scan and white light bronchoscopy is not associated with life-threatening complications.

Sequential screening for lung cancer in a high-risk group: randomised controlled trial: LungSEARCH: a randomised controlled trial of Surveillance using sputum and imaging for the EARly detection of lung Cancer in a High-risk group

BACKGROUND

Low-dose computed tomography (LDCT) screening detects early-stage lung cancer and reduces mortality. We proposed a sequential approach targeted to a high-risk group as a potentially efficient screening strategy.

METHODS

LungSEARCH was a national multicentre randomised trial. Current/ex-smokers with mild/moderate chronic obstructive pulmonary disease (COPD) were allocated (1:1) to have 5 years surveillance or not. Screened participants provided annual sputum samples for cytology and cytometry, and if abnormal were offered annual LDCT and autofluorescence bronchoscopy (AFB). Those with normal sputum provided annual samples. The primary end-point was the percentage of lung cancers diagnosed at stage I/II (nonsmall cell) or limited disease (small cell).

RESULTS

1568 participants were randomised during 2007-2011 from 10 UK centres. 85.2% of those screened provided an adequate baseline sputum sample. There were 42 lung cancers among 785 screened individuals and 36 lung cancers among 783 controls. 54.8% (23 out of 42) of screened individuals versus 45.2% (14 out of 31) of controls with known staging were diagnosed with early-stage disease (one-sided p=0.24). Relative risk was 1.21 (95% CI 0.75-1.95) or 0.82 (95% CI 0.52-1.31) for early-stage or advanced cancers, respectively. Overall sensitivity for sputum (in those randomised to surveillance) was low (40.5%) with a cumulative false-positive rate (FPR) of 32.8%. 55% of cancers had normal sputum results throughout. Among sputum-positive individuals who had AFB, sensitivity was 45.5% and cumulative FPR was 39.5%; the corresponding measures for those who had LDCT were 100% and 16.1%, respectively.

CONCLUSIONS

Our sequential strategy, using sputum cytology/cytometry to select high-risk individuals for AFB and LDCT, did not lead to a clear stage shift and did not improve the efficiency of lung cancer screening.

Real-time endoscopic Raman spectroscopy for in vivo early lung cancer detection

Currently the most sensitive method for localizing lung cancers in central airways is autofluorescence bronchoscopy (AFB) in combination with white light bronchoscopy (WLB). The diagnostic accuracy of WLB + AFB for high grade dysplasia (HGD) and carcinoma in situ is variable depending on physician's experience. When WLB + AFB are operated at high diagnostic sensitivity, the associated diagnostic specificity is low. Raman spectroscopy probes molecular vibrations and gives highly specific, fingerprint-like spectral features and has high accuracy for tissue pathology classification. In this study we present the use of a real-time endoscopy Raman spectroscopy system to improve the specificity. A spectrum is acquired within 1 second and clinical data are obtained from 280 tissue sites (72 HGDs/malignant lesions, 208 benign lesions/normal sites) in 80 patients. Using multivariate analyses and waveband selection methods on the Raman spectra, we have demonstrated that HGD and malignant lung lesions can be detected with high sensitivity (90%) and good specificity (65%).

Development of a Fluorescence Detection System Using Optical Parametric Oscillator (OPO) Laser Excitation for in Vivo Diagnosis

In this work, the development and applications of a fluorescence detection system using optical parametric oscillator (OPO) laser excitation for in vivo disease diagnosis including oral carcinoma are described. The optical diagnosis system was based on an OPO laser for multi-wavelength excitation and time-resolved detection. The pulsed Nd-YAG-pumped OPO laser system (6 ns, 20 Hz) is compact and has a rapid, broad, and uniform tuning range. Time-gated detection of intensified charge-coupled device (ICCD) making use of external triggering was used to effectively eliminate the laser scattering and contribute to the highly sensitive in vivo measurements. Artificial tissue-simulating phantoms consisting of polystyrene microspheres and tissue fluorophores were tested to optimize the gating parameters. 51-ns gate width and 39-ns gate delays were determined to be the optimal parameters for sensitive detection. in vivo measurements with the optical diagnosis system were applied to esophagus, stomach, and small intestine using an endoscope in canine animal studies. The rapid tuning capability of the optical diagnosis system contributed greatly to the optimization of wavelength for the observation of porphyrin in the small intestine. When the small intestine was thoroughly washed with water, the emission band which corresponds to porphyrin disappeared. Based on this observation, it was concluded that the detected signal was yielded by porphyrin-containing bile secretion. Also, multispectral analyses using multiple excitations from 415 to 480 nm at 5 nm intervals confirmed the porphyrin detection in the small intestine. The optical diagnosis system was also applied to the detection of human xenograft of oral carcinoma in mice using 5-aminolevulinic acid (5-ALA) which is a photodynamic therapy (PDT) drug. Significant differences in protoporphyrin IX fluorescence intensity between normal and tumor tissue could be obtained 2 hours after the injection of 5-ALA into mice due to the preferential accumulation of 5-ALA in tumors. Results reported herein demonstrate potential capabilities of the LIF-OPO system for in vivo disease diagnosis.

The use of light-based (optical) detection systems as adjuncts in the detection of oral cancer and oral potentially malignant disorders: a systematic review

INTRODUCTION

In recent decades, optical techniques utilising the principles of chemiluminescence and tissue autofluorescence have emerged to facilitate the early detection of any oral mucosal changes suspicious of cancer.

PURPOSE

To evaluate the effectiveness of devices that utilise the principles of chemiluminescence and tissue autofluorescence as adjuncts in the detection of oral cancer and oral potentially malignant disorders (OPMDs).

METHODS

A systematic review of the published literature to evaluate the effectiveness of the ViziLite(®) and ViziLite(®) Plus with toluidine blue, MicroLux™/DL and the VELscope™ as aids in the detection of oral cancer and OPMDs.

RESULTS

Twenty-five primary studies published between 2004 and 2013 satisfied our criteria for selection - 13 utilised chemiluminescence and 12 tissue autofluorescence. Some had utilised both study methods on the same population. Chemiluminescence shows good sensitivity at detecting any OPMDs and oral cancer. However, it preferentially detects leukoplakia and may fail to spot red patches. The additive use of toluidine blue may improve specificity. Tissue autofluorescence is sensitive at detecting white, red and white and red patches, and the area of fluorescence visualisation loss (FVL) often extends beyond the clinically visible lesion. However, in addition to OPMDs, VELScope may detect erythematous lesions of benign inflammation resulting in false-positive test results.

CONCLUSION

There is limited evidence for their use in primary care, and these tools are better suited to specialist clinics in which there is a higher prevalence of disease and where experienced clinicians may better discriminate between benign and malignant lesions.

Photodynamic diagnoses of malignant pleural diseases using the autofluorescence imaging system

BACKGROUND

We conducted a study on photodynamic diagnosis (PDD) using autofluorescence in video-assisted thoracic surgery for minute intrathoracic small dissemination or early malignant pleural mesothelioma.

METHODS

Autofluorescence is the spontaneous emission of light that occurs when mitochondria, lysosomes, and other intracellular organelles absorb light. In normal tissues, green autofluorescence of approximately 520 nm is observed in response to 400-450 nm blue excitation rays. However, in cancer lesions, green autofluorescence is reduced due to thickening of the mucosal epithelium, a decrease in autofluorescent substances, etc., and the color spectrum thus shifts to red-violet. This phenomenon is the basis of PDD.

RESULTS

The color spectrum shift was observed in all tumors located on the pleural surface but not in cases with pleural fibrous disease. Among patients with primary lung cancer, those with pleural infiltration (pl) scores of 1 or greater showed color spectrum shifts due to reduced autofluorescence.

CONCLUSION

Localization of pleural lesions by autofluorescence imaging was found to be useful. In primary lung cancer cases, differentiation between pl0 and pl1 lesions appears to be useful for determining therapeutic strategies including surgical procedures.

Analysis of surgical margins in oral cancer using in situ fluorescence spectroscopy

Oral cancer is a public health problem with high prevalence in the population. Local tumor control is best achieved by complete surgical resection with adequate margins. A disease-free surgical margin correlates with a lower rate of local recurrence and a higher rate of disease-free survival. Fluorescence spectroscopy is a noninvasive diagnostic tool that can aid in real-time cancer detection. The technique, which evaluates the biochemical composition and structure of tissue fluorescence, is relatively simple, fast and, accurate.

OBJECTIVES

This study aimed to compare oral squamous cell carcinoma lesions to surgical margins and the mucosa of healthy volunteers by fluorescence spectroscopy.

MATERIALS AND METHODS

The sample consisted of 56 individuals, 28 with oral squamous cell carcinoma and 28 healthy volunteers with normal oral mucosa. Thirty six cases (64.3%) were male and the mean age was 60.9 years old. The spectra were classified and compared to histopathology to determine fluorescence efficiency for diagnostic discrimination of tumors.

RESULTS

In the analysis of the other cases we observed discrimination between normal mucosa, injury and margins. At two-year follow up, three individuals had local recurrence, and in two cases investigation fluorescence in the corresponding area showed qualitative differences in spectra between the recurrence area and the area without recurrence at the same anatomical site in the same patient.

CONCLUSION

In situ analysis of oral mucosa showed the potential of fluorescence spectroscopy as a diagnostic tool that can aid in discrimination of altered mucosa and normal mucosa.

Is there a relationship between the presence of lung mucosa preinvasive lesions and lung cancer incidence? Influence of tobacco consumption

Although studied for years, the nature of the relationships between tobacco consumption, bronchial preinvasive lesions and lung cancer are still not completely elucidated. Objectives were to determine the relationship between tobacco consumption and lung mucosa preinvasive and invasive lesions and to describe patients' evolution according to baseline characteristics.

METHODS

Bronchial biopsy specimens were taken at six predetermined sites in 156 males, current smokers, aged above 18 years. Relationships between smoking characteristics and preinvasive lesions indexes and between baseline characteristics and lung cancer occurrence during a prospective follow-up were examined.

RESULTS

Maximum grade was hyperplasia for 16.7% of patients, metaplasia 33.3%, dysplasia 25.0%, and carcinoma in situ 1.3%. For 23.7% of patients, all biopsies were considered normal. Preinvasive lesion indexes were related to smoking intensity (cigarettes/day). Lung cancer incidence during the follow-up was 19.9%. No association between severity of mucosa lesions at baseline and incidence of cancer during the follow-up period was observed.

CONCLUSION

The majority of smokers had mucosa lesions, but a relatively small number of them would have a cancer, and there was a poor correlation between severity of mucosalesions and incidence of cancer. Even if an evolution from preinvasive lesions to an invasive cancer is plausible and coherent with current concepts, this link does not appear strong enough to recommend the use of systematic classic endoscopy for targeting of a sub-group of higher risk smokers who would require a closer follow up.

Fluorescein derivatives in intravital fluorescence imaging

Intravital fluorescence microscopy enables the direct imaging of fluorophores in vivo and advanced techniques such as fluorescence lifetime imaging (FLIM) enable the simultaneous detection of multiple fluorophores. Consequently, it is now possible to record distribution and metabolism of a chemical in vivo and to optimise the delivery of fluorophores in vivo. Recent clinical applications with fluorescein and other intravital fluorescent stains have occurred in neurosurgery, dermatology [including photodynamic therapy (PDT)] and endomicroscopy. Potential uses have been identified in periodontal disease, skin graft and cancer surgery. Animal studies have demonstrated that diseased tissue can be specifically stained with fluorophore conjugates. This review focuses on the fluorescein derived fluorophores in common clinical use and provides examples of novel applications from studies in tissue samples.

Diagnosis and treatment of bronchial intraepithelial neoplasia and early lung cancer of the central airways: Diagnosis and management of lung cancer, 3rd ed: American College of Chest Physicians evidence-based clinical practice guidelines

BACKGROUND

Bronchial intraepithelial lesions may be precursors of central airway lung carcinomas. Identification and early treatment of these preinvasive lesions might prevent progression to invasive carcinoma.

METHODS

We systematically reviewed the literature to develop evidence-based recommendations regarding the diagnosis and treatment of intraepithelial lesions.

RESULTS

The risk and timeline for progression of bronchial intraepithelial lesions to carcinoma in situ (CIS) or invasive carcinoma are not well understood. Multiple studies show that autofluorescence bronchoscopy (AFB) is more sensitive that white light bronchoscopy (WLB) to identify these lesions. In patients with severe dysplasia or CIS in sputum cytology who have chest imaging studies showing no localizing abnormality, we suggest use of WLB; AFB may be used as an adjunct when available. Patients with known severe dysplasia or CIS of central airways should be followed with WLB or AFB, when available. WLB or AFB is also suggested for patients with early lung cancer who will undergo resection for delineation of tumor margins and assessment of synchronous lesions. However, AFB is not recommended prior to endobronchial therapy for CIS or early central lung cancer. Several endobronchial techniques are recommended for the treatment of patients with superficial limited mucosal lung cancer who are not candidates for resection.

CONCLUSION

Additional information is needed about the natural history and rate of progression of preinvasive central airway lesions. Patients with severe dysplasia or CIS may be treated endobronchially; however, it remains unclear if these therapies are associated with improved patient outcomes.

LED light source for fluorescence endoscopy using quantum dots

We present an LED light source for use with standard clinical endoscopes to enable visualization of tissues labeled with quantum dots (QDs). QD-assisted endoscopy may improve the outcome of surgical endoscopic procedures by identifying specific tissue types. QDs offer several advantages over current fluorescent stains due to their high target selectivity, long-lasting fluorescence, large excitation and narrow emission bands, and multiplexing capabilities. The prototype presented is compact, modular in design, and was built at low cost making it competitive with commercially available light sources. The device's efficiency is evaluated by measuring light intensity at discreet locations and by successfully illuminating a chicken tissue sample non-specifically labeled with a 250nM or 500nM QD solution. Ultimately, this device serves as a step towards incorporating QDs into real time, image-guided surgical procedures.

The effect of reactive atypia/inflammation on the laser-induced fluorescence diagnosis of non-dysplastic Barrett's esophagus

BACKGROUND AND OBJECTIVES

Differential Normalized Fluorescence (DNF) technique has been used to distinguish high-grade dysplasia from non-dysplastic Barrett's esophagus. This technology may assist gastroenterologists in targeting biopsies, reducing the number of biopsies using the standard protocol. In the presence of reactive atypia/inflammation, it becomes difficult for the pathologist to differentiate non-dysplastic Barrett's esophagus from Barrett's esophagus with low-grade dysplasia. Before DNF technique may be used to guide target biopsies, it is critical to know whether reactive atypia/inflammation in non-dysplastic Barrett's may result in false positives. This study was conducted to determine whether DNF technique is adversely affected by the presence of reactive atypia/inflammation in non-dysplastic Barrett's esophagus resulting in false positives.

STUDY DESIGN/MATERIALS AND METHODS

Four hundred ten-nanometer laser light was used to induce autofluorescence of Barrett's mucosa in 49 patients. The clinical study included 37 males and 12 females. This was a blinded retrospective data analysis study. A total of 303 spectra were collected and matched to non-dysplastic Barrett's biopsy results. One hundred seventy-five spectra were collected from areas with a pathology of non-dysplastic Barrett's esophagus with reactive atypia/inflammation. One hundred twenty-eight spectra were collected from areas with non-dysplastic Barrett's esophagus without reactive changes/inflammation. The spectra were analyzed using the DNF Index at 480 nm and classified as positive or negative using the threshold of -0.75 × 10(-3).

RESULTS

Using DNF technique, 92.6% of non-dysplastic samples with reactive atypia/inflammation were classified correctly (162/175). 92.2% of non-dysplastic samples without reactive atypia/inflammation were classified correctly (118/128). Comparing the ratios of false positives among the two sample groups, there was not a statistically significant difference between the two groups.

CONCLUSION

Using DNF technique for classification of non-dysplastic Barrett's mucosa does not result in false-positive readings due to reactive atypia/inflammation. Target biopsies guided by DNF technique may drastically reduce the number of pinch biopsies using the standard biopsy protocol.

Preinvasive lesions of the bronchus

It has been proposed that invasive carcinoma of the bronchus develops through a transition from preinvasive lesions to overt malignancy. Newer diagnostic technologies have provided a more sensitive way to diagnose preinvasive lesions and a better understanding of the prevalence of such lesions. The natural history of preinvasive lesions has not been well defined; however, there is evidence that high-grade lesions are at a higher risk of progression to carcinoma. Molecular alterations have been described in preinvasive lesions and may help better predict which lesions will progress. Several noninvasive techniques are available for the treatment of high-grade lesions.

Frontiers in bronchoscopic imaging

Bronchoscopy is a minimally invasive method for diagnosis of diseases of the airways and the lung parenchyma. Standard bronchoscopy uses the reflectance/scattering properties of white light from tissue to examine the macroscopic appearance of airways. It does not exploit the full spectrum of the optical properties of bronchial tissues. Advances in optical imaging such as optical coherence tomography (OCT), confocal endomicroscopy, autofluorescence imaging and laser Raman spectroscopy are at the forefront to allow in vivo high-resolution probing of the microscopic structure, biochemical compositions and even molecular alterations in disease states. OCT can visualize cellular and extracellular structures at and below the tissue surface with near histological resolution, as well as to provide three-dimensional imaging of the airways. Cellular and subcellular imaging can be achieved using confocal endomicroscopy or endocytoscopy. Contrast associated with light absorption by haemoglobin can be used to highlight changes in microvascular structures in the subepithelium using narrow-band imaging. Blood vessels in the peribronchial space can be displayed using Doppler OCT. Biochemical compositions can be analysed with laser Raman spectroscopy, autofluorescence or multispectral imaging. Clinically, autofluorescence and narrow-band imaging have been found to be useful for localization of preneoplastic and neoplastic bronchial lesions. OCT can differentiate carcinoma in situ versus microinvasive cancer. Endoscopic optical imaging is a promising technology that can expand the horizon for studying the pathogenesis and progression of airway diseases such as COPD and asthma, as well as to evaluate the effect of novel therapy.

Spectral investigations of the interaction of some porphyrins with bovine serum albumin

The binding of meso-tetrakis[4-(carboxymethyleneoxy)phenyl]porphyrin (T4CPP), meso-tetrakis[3-(carboxymethyleneoxy)phenyl]porphyrin (T3CPP) and meso-tetrakis[3,4-bis(carboxymethyl-eneoxy)phenyl]porphyrin (T3, 4BCPP) with bovine serum albumin (BSA) at pH 7.4 has been studied at 420 nm in detail. The results show hypochromicity along with a red shift in the Soret band of the porphyrins. This suggests that these porphyrins bind to BSA as monomers. Further analysis of these data supports the non-interactive binding of T4CPP and T3CPP with BSA and the cooperative binding of T3, 4BCPP with BSA. These binding data have been interpreted in terms of one specific binding site and several non-specific binding sites on BSA for the porphyrins. The absorption spectral changes of the porphyrins between 400 and 450 nm when titrated with BSA suggest that there is another specific binding site on BSA for the porphyrins. These two specific binding sites have also been supported by circular dichroism (CD) studies. The absorption spectral and CD studies on the interactions of the porphyrins with BSA further suggest that these interactions are dependent on the number and configuration of substituents in the phenyl groups of the porphyrins. The contact energy transfer from the aromatic amino acid residues tryptophan and tyrosine of BSA to the porphyrins in the BSA–porphyrin complexes has also been studied using fluorescence spectroscopy. These energy transfer data show the energy transfer from tryptophan to the porphyrins for their binding to site I of BSA and from tyrosine to the porphyrins for their binding to site II of BSA. Unfolding studies of the BSA–porphyrin systems indicate that the tertiary structure is essential for the binding of the porphyrins. A correlation between the accumulation of99 mTc -labelled T4CPP and T3, 4BCPP in tumour tissue and their binding at site II of BSA is possible. The interaction of the porphyrins can also be used as a model for mitochondrial interactions.

Optical detection of preneoplastic lesions of the central airways

Current routine diagnosis of premalignant lesions of the central airways is hampered due to a limited sensitivity (white light bronchoscopy) and resolution (computer tomography (CT), positron emission tomography (PET)) of currently used techniques. To improve the detection of these subtle mucosal abnormalities, novel optical imaging bronchoscopic techniques have been developed over the past decade. In this review we highlight the technological developments in the field of endoscopic imaging, and describe their advantages and disadvantages in clinical use.

Using laser Raman spectroscopy to reduce false positives of autofluorescence bronchoscopies: a pilot study

INTRODUCTION

Preneoplastic lesions of the bronchial tree have a high probability of developing into malignant tumors. Currently, the best method for localizing them for further treatment is a combined white light bronchoscopy (WLB) and autofluorescence bronchoscopy (AFB) (WLB + AFB). The average specificity from large clinical trials for this combined detection method is approximately 60%, leading to many false positives. The object of this study is to determine whether adding point laser Raman spectroscopy (LRS) to a WLB + AFB has the potential to improve the specificity of preneoplastic lesion detection and what the implication is to the detection sensitivity.

METHODS

An LRS system was developed to collect real-time, in vivo lung spectra with a fiber optic catheter passed down the instrument channel of a bronchoscope. WLB + AFB imaging modalities were used to identify lesions from 26 subjects, from which 129 Raman spectra were measured. Multivariate statistical analyses were performed on the spectra with a leave-one-out crossvalidation.

RESULTS

Clear in vivo Raman spectra were obtained in 1 second. The location of individual Raman peaks in the spectra correlated well with the known positions of Raman peaks generated by lipids, proteins, and water molecules. Preneoplastic lesions were detected with a sensitivity of 96% and a specificity of 91%.

CONCLUSION

Adding point LRS analysis to WLB + AFB imaging has the ability to detect preneoplastic lesions in real time with high sensitivity and specificity. The use of LRS has great potential for substantially reducing the number of false-positive biopsies associated with WLB + AFB with very little reduction in the detection sensitivity.

Application of autofluorescence endoscopy for colorectal cancer screening: rationale and an update

As the result of basic researches, several intravital fluorophores have been determined so far in human colorectal tissue. Autofluorescence endoscopy (AFE) can detect slight alterations in their distribution and concentration during the colorectal carcinogenesis process and, thus facilitate noninvasive screening colonoscopies without the need for fluorescent substances or staining reagents to be administered. While detecting faint autofluorescence intensity by conventional fiberoptic endoscopy remains challenging, the latest AFE system with high-resolution videoendoscope capabilities enables such detection by using a false-color display algorithm. To this end, the diagnostic benefits of AFE have been reported in several multicenter randomized controlled studies of colorectal cancer (CRC) screening and differential diagnosis. CRC screening using the latest AFE technology could, therefore, lead to future reductions in CRC mortality.

Altered histology provides a positive clinical signal in the bronchial epithelium

The history of lung cancer chemoprevention trials has been uniformly disappointing in that the large phase III studies showed no effect or harm in actively smoking participants, and smaller phase II studies have also been negative. In this issue of the journal (beginning on page 793), Keith and colleagues report their randomized, placebo-controlled trial of the oral prostacyclin analogue iloprost, the first trial to show an improvement in bronchial histology (i.e., regression), which occurred in former, but not current, smokers with sputum atypia. This Perspective discusses the strength of the clinical signal provided by this observation and its implications for further drug development.

Autofluorescence imaging can identify preinvasive or clinically occult lesions in fallopian tube epithelium: a promising step towards screening and early detection

BACKGROUND

Optical imaging systems are robust, portable, relatively inexpensive, and have proven utility in detecting precancerous lesions in the lung, esophagus, colon, oral cavity and cervix. We describe the use of light-induced endogenous fluorescence (autofluorescence) in identifying preinvasive and occult carcinomas in ex vivo samples of human fallopian tube (FT) epithelium.

METHODS

Women undergoing surgery for an i) ovarian mass, ii) a history suggestive of hereditary breast-ovarian cancer, or iii) known serous ovarian cancer following neoadjuvant chemotherapy (NAC) were approached for informed consent. Immediately following surgery, FT's were photographed in reflectance and fluorescence at high resolution. Images included: (1) white-light reflectance of luminal/epithelial surface; (2) narrow-band green reflectance (570 nm) (3) green autofluorescence (405/436 nm excitation); and (4) blue autofluorescence (405 nm excitation). Areas revealing a loss of natural tissue fluorescence or marked increase in tissue microvasculature were recorded and compared to final histopathologic diagnosis (SEE-FIM protocol).

RESULTS

Fifty-six cases involving one or both fallopian tubes underwent reflectance and fluorescence visualization. Nine cases were excluded, either secondary to non-ovarian primary pathology (7) or excessive trauma (2) rendering tissue interpretation impossible. Of the 47 cases remaining, there were 11 high grade serous (HGS) and 9 non-serous ovarian carcinomas undergoing primary debulking surgery, 5 serous carcinomas having received NAC, 8 benign ovarian tumors, and 14 women undergoing risk-reducing bilateral salpingo-oophorectomy (RRBSO). Methodology was feasible, efficient, and reproducible. TIC or carcinoma was identified in 7/11 HGS, 3/5 NAC, and 1/14 RRBSO. Optical images were reviewed to determine test positive or negative based on standardized criteria. Sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) were calculated for the entire cohort (73%; 83%; 57%; 91%) and in a subgroup that excluded non-serous histology (87.5%; 92%; 78%; 96%).

CONCLUSIONS

Abnormal FT lesions can be identified using ex vivo optical imaging technologies. With this platform, we will move towards genomic interrogation of identified lesions, and developing in vivo screening modalities via falloposcopy.

Natural history of bronchial preinvasive lesions

Preinvasive bronchial lesions defined as dysplasia and carcinoma in situ (CIS) have been considered as precursors of squamous cell carcinoma of the lung. The risk and rate of progression of preinvasive lesions to invasive squamous cell carcinoma as well as the mechanism of progression or regression are incompletely understood. While the evidence for the multistage, stepwise progression model is weak with relatively few documented lesions that progress through various grades of dysplasia to CIS and then to invasive carcinoma, the concept of field carcinogenesis is strongly supported. The presence of high-grade dysplasia or CIS is a risk marker for lung cancer both in the central airways and peripheral lung. Genetic alterations such as loss of heterozygosity in chromosome 3p or chromosomal aneusomy as well as host factors such as the inflammatory load and levels of anti-inflammatory proteins in the lung influence the progression or regression of preinvasive lesions. CIS is different than severe dysplasia at the molecular level and has different clinical outcome. Molecular analysis of dysplastic lesions that progress to CIS or invasive cancer and rare lesions that progress rapidly from hyperplasia or metaplasia to CIS or invasive cancer will shed light on the key molecular determinants driving development to an invasive phenotype versus those associated with tobacco smoke damage.

An up to date look at lung cancer screening

Lung cancer is the leading cause of cancer-related death worldwide. At the time of initial presentation, most patients are at an advance stage of disease and have a poor associated prognosis. Those diagnosed and treated at earlier stages have a significantly better outcome with 5-year survival for stage I disease approaching 75%. Ideally a screening strategy for lung cancer would detect disease at an earlier stage and allow for potential surgical cure. The purpose of this review is to examine past and current evidence as it relates to lung cancer screening.

[Early diagnosis of lung cancer: impact of autofluorescence bronchoscopy]

INTRODUCTION

Less than 15% of all patients survive five years after a diagnosis of lung cancer. This poor prognosis is attributed to a lack of early detection. Among the methods of early diagnosis of bronchial cancer, autofluorescence bronchoscopy allows for the early identification of preinvasive bronchial lesions. The goal of this prospective study is to evaluate the contribution of the autofluorescence bronchoscopy, on a hospital site, over a period of one year.

METHODS

All patients with an indication of autofluorescence bronchoscopy were included in the study. The following parameters were collected: age, sex, smoking status, FEV1, FVC, biopsy sites, histology, duration of examination.

RESULTS

Two hundred and seventy-four patients were included. The average age was 63.8 years (+/-12), the smoking status was 35 packs/year (+/-19). A fluorescence abnormality was detected in 131 patients and 165 sites were biopsied. An histological abnormality was found in 76% of the samples, with 34 hyperplasia (28%), 56 squamous metaplasia (46%), three mild dysplasia (3%), two moderate dysplasia (2%), one severe dysplasia (1%), two carcinomas in situ (2%) and 21 invasive carcinomas (18%).

CONCLUSION

Autofluorescence bronchoscopy is an effective examination for the detection of the preinvasive neoplasic lesions and may be proposed when lung cancer is suspected.

Pulmonary preneoplasia--sequential molecular carcinogenetic events

Bronchial and bronchioloalveolar carcinogenesis is a multicentric and multistep process, leading to a sequential accumulation of molecular and genetic abnormalities, mainly due to exposure to tobacco carcinogens. Concomitantly, a series of morphological alterations of normal bronchial or bronchioloalveolar epithelium occur, resulting in preneoplastic and then neoplastic lesions. The three pulmonary preneoplastic changes recognized to date in the lung include bronchial squamous dysplasia and in situ carcinoma, preceding invasive squamous cell carcinoma and basaloid carcinoma, atypical adenomatous hyperplasia, a preneoplastic condition of bronchioloalveolar carcinoma, and diffuse idiopathic pulmonary neuroendocrine cell hyperplasia, a proposed precursor for carcinoid tumours. Although the gradual accumulation of molecular alterations has been widely investigated in bronchial carcinogenesis, with the aim of determining new biomarkers for early lung cancer detection in high-risk patients and targeted chemoprevention, lung adenocarcinoma pathogenesis has been only recently highlighted, with the recent discovery of epidermal growth factor receptor mutation pathway in non-smokers. This review focuses on the current status of molecular pathology in lung cancer and pulmonary preneoplastic conditions.

Detection and localization of intraepithelial neoplasia and invasive carcinoma using fluorescence-reflectance bronchoscopy: an international, multicenter clinical trial

OBJECTIVES

The primary objective of this study was to evaluate the benefit of using a new fluorescence-reflectance imaging system, Onco-LIFE, for the detection and localization of intraepitheal neoplasia and early invasive squamous cell carcinoma. A secondary objective was to evaluate the potential use of quantitative image analysis with this device for objective classification of abnormal sites.

DESIGN

This study was a prospective, multicenter, comparative, single arm trial. Subjects for this study were aged 45 to 75 years and either current or past smokers of more than 20 pack-years with airflow obstruction, forced expiratory volume in 1 second/forced vital capacity less than 75%, suspected to have lung cancer based on either sputum atypia, abnormal chest roentgenogram/chest computed tomography, or patients with previous curatively treated lung or head and neck cancer within 2 years.

MATERIALS AND METHODS

The primary endpoint of the study was to determine the relative sensitivity of white light bronchoscopy (WLB) plus autofluorescence-reflectance bronchoscopy compared with WLB alone. Bronchoscopy with Onco-LIFE was carried out in two stages. The first stage was performed under white light and mucosal lesions were visually classified. Mucosal lesions were classified using the same scheme in the second stage when viewed with Onco-LIFE in the fluorescence-reflectance mode. All regions classified as suspicious for moderate dysplasia or worse were biopsied, plus at least one nonsuspicious region for control. Specimens were evaluated by the site pathologist and then sent to a reference pathologist, each blinded to the endoscopic findings. Positive lesions were defined as those with moderate/severe dysplasia, carcinoma in situ (CIS), or invasive carcinoma. A positive patient was defined as having at least one lesion of moderate/severe dysplasia, CIS, or invasive carcinoma. Onco-LIFE was also used to quantify the fluorescence-reflectance response (based on the proportion of reflected red light to green fluorescence) for each suspected lesion before biopsy.

RESULTS

There were 115 men and 55 women with median age of 62 years. Seven hundred seventy-six biopsy specimens were included. Seventy-six were classified as positive (moderate dysplasia or worse) by pathology. The relative sensitivity on a per-lesion basis of WLB + FLB versus WLB was 1.50 (95% confidence interval [CI], 1.26-1.89). The relative sensitivity on a per-patient basis was 1.33 (95% CI, 1.13-1.70). The relative sensitivity to detect intraepithelial neoplasia (moderate/severe dysplasia or CIS) was 4.29 (95% CI, 2.00-16.00) and 3.50 (95% CI, 1.63-12.00) on a per-lesion and per-patient basis, respectively. For a quantified fluorescence reflectance response value of more than or equal to 0.40, a sensitivity and specificity of 51% and 80%, respectively, could be achieved for detection of moderate/severe dsyplasia, CIS, and microinvasive cancer.

CONCLUSIONS

Using autofluorescence-reflectance bronchoscopy as an adjunct to WLB with the Onco-LIFE system improves the detection and localization of intraepitheal neoplasia and invasive carcinoma compared with WLB alone. The use of quantitative image analysis to minimize interobserver variation in grading of abnormal sites should be explored further in future prospective clinical trial.

Model-based analysis of reflectance and fluorescence spectra for in vivo detection of cervical dysplasia and cancer

Development, validation, and implementation of an analytical model to extract biologically and diagnostically relevant parameters from measured cervical tissue reflectance and fluorescence spectra are presented. Monte Carlo simulations of tissue reflectance are used to determine the relative contribution of the signal from the epithelium and stroma. The results indicate that the clinical probe used collects a majority of its reflectance signal from the stroma; therefore, a one-layer analytical model of reflectance is used. Two analytical approaches to calculate reflectance spectra are compared to Monte Carlo simulations, and a diffusion theory-based model is implemented. The model is validated by fitting spectra generated from Monte Carlo simulations and comparing the input and output parameters. Median agreement between extracted optical properties and input parameters is 10.6%. The reflectance model is used together with an analytical model of tissue fluorescence to extract optical properties and fluorophore concentrations from 748 clinical measurements of cervical tissue. A diagnostic algorithm based on these extracted parameters is developed and evaluated using cross-validation. The sensitivity/specificity of this algorithm relative to the gold standard of histopathology per measurement are 8551%; this is comparable to accuracy reported in other studies of optical technologies for detection of cervical cancer and its precursors.

The role of autofluorescence diagnostics in the oral mucosa diseases

BACKGROUND

Laser-induced fluorescence diagnostics (LIFE) can be used as an imaging system of precancerous and neoplasmatic lesions of oral mucosa. LIFE system utilizes healthy and neoplasmatically changed tissue in autofluorescence, without using any fluorescence substances. Neoplasmatic lesions are visible in pseudo colors, healthy tissue as a shade of green color and abnormal tissue as a shade of red color. All visible colors have different intensity. Color intensity is relevant to the grade of dysplasia, carcinoma progress and is called numerical color value (NCV).

AIM

The aim of our study was to find correlation between autofluorescence diagnostics with NCV assessment and type of histopathological diagnostics of specimen biopsy.

PATIENTS AND METHODS

Fourteen patients participated in our study. Lesions were located in different intraoral areas. The most common location was: buccal, gingival and mandibular mucosa. Patients were examined using laser induced fluorescence diagnostics (400-750 nm wavelength) with NCV using OncoLIFE system. Then the specimen biopsy from the lesion was taken and histopathological examination was performed.

RESULTS

We have noted different NCV and dependence of NCV on histopathological grade.

CONCLUSION

Diagnostics using white-light imaging with LIFE imaging is not only a significant faster method and a better diagnostics of preneoplasmatic and neoplasmatic lesions, but also there is a correlation between NCV and histopathological grade. The farther investigations are necessary to prove these preliminary findings.

Autofluorescence bronchoscopy in volunteer asymptomatic smokers

We assess the sensitivity of autofluorescence bronchoscopy (AFB) compared to that of white light bronchoscopy (WLB) for identification of pre-invasive neoplastic changes of bronchial mucosa in asymptomatic heavy smokers. WLB was performed using a standard flexible fibre-optic bronchoscope, and AFB carried out using the Xillix LIFE Lung((R)) system. Positive AFB images were indicated in the bronchial tree from 51 of the 93 subjects in the study. Biopsies showed epithelial abnormalities in 27 (15 metaplasia, 12 inflammatory changes) of these. WLB showed abnormality in 1 subject but with no pathological changes revealed by cyto-histology. Therefore, the sensitivity of AFB to metaplasia was 75% compared to zero for WLB. AFB yields positive predictive values for metaplastic and overall mucosal changes of 29.4% and 52.9%, respectively. In summary, over 16% of asymptomatic smokers had metaplastic changes in their bronchial mucosa, and AFB proved more sensitive in revealing early changes than WLB.

Pulmonary Preneoplasia

Context.—Improved screening techniques for lung cancer have resulted in detection of lesions that are considered to represent precursors of invasive lung carcinomas. These lesions may cause a diagnostic dilemma particularly on small biopsy or cytology specimens. Ancillary studies are usually not helpful, and diagnosis is based on morphology alone. Recognition of these lesions is very important to prevent potential diagnostic mistakes that may result in inadequate patient management. Future molecular studies may provide clinically useful diagnostic and prognostic gene markers.

Objective.—To review currently proposed morphologic criteria for precursor lesions of non–small cell lung carcinomas including squamous dysplasias, atypical adenomatous hyperplasia, and diffuse idiopathic neuroendocrine cell hyperplasia. Major molecular abnormalities are briefly discussed.

Data Sources.—Published literature and recent World Health Organization classification of lung tumors.

Conclusions.—Practicing surgical pathologists must be familiar with morphology of recognized pulmonary preneoplastic lesions that are more frequently detected radiographically and subjected to diagnostic procedures. Future understanding of underlying molecular abnormalities associated with progression of these lesions into invasive lung carcinoma may result in a development of molecular assays with potential diagnostic and prognostic importance.

Development and preliminary results of an endoscopic Raman probe for potential in vivo diagnosis of lung cancers

A near-infrared Raman system was developed to collect real-time in vivo human lung spectra. The excitation light and the emission were guided to and from the tissue surface by a reusable fiber catheter passed down the instrument channel of a bronchoscope. Two-stage filtering was used to reduce laser noise, fluorescence, and Raman emissions from the fibers. A second fiber bundle guided the emission to a spectrometer where the fibers, in a round packing geometry, were spread out to form a parabolic arc that improved the signal-to-noise ratio 20-fold, facilitating real-time spectral measurements. Preliminary clinical tests show that clear and reliable Raman spectra can be obtained.

Critical evaluation of diagnostic aids for the detection of oral cancer

Historically, the screening of patients for signs of oral cancer and precancerous lesions has relied upon the conventional oral examination. A variety of commercial diagnostic aids and adjunctive techniques are available to potentially assist in the screening of healthy patients for evidence of otherwise occult cancerous change or to assess the biologic potential of clinically abnormal mucosal lesions. This manuscript systematically and critically examines the literature associated with current oral cancer screening and case-finding aids or adjuncts such as toluidine blue, brush cytology, tissue reflectance and autofluorescence. The characteristics of an ideal screening test are outlined and the authors pose several questions for clinicians and scientists to consider in the evaluation of current and future studies of oral cancer detection and diagnosis. Although the increased public awareness of oral cancer made possible by the marketing of recently-introduced screening adjuncts is commendable, the tantalizing implication that such technologies may improve detection of oral cancers and precancers beyond conventional oral examination alone has yet to be rigorously confirmed.

Autofluorescence bronchoscopy, a novel modality for the early detection of bronchial premalignant and malignant lesions

Lung cancer is the leading cause of cancer deaths in developed countries. Recently, autofluorescence bronchoscopy has been reported to improve the early detection of lung cancer in high-risk individuals. In the present study, we evaluated the efficacy of autofluorescence bronchoscopy for the early detection of bronchial premalignant and malignant lesions. From November 2000 through March 2004, 123 high-risk individuals (114 men and 9 women with a mean age of 68 years) were enrolled. Among 282 biopsy specimens, 93 (33.0%) were premalignant or malignant lesions. The sensitivity and negative predictive value for the detection of bronchial premalignant and malignant lesions were significantly higher with the addition of autofluorescence bronchoscopy than white light bronchoscopy alone. Moreover, the sensitivity for the detection of bronchial premalignant lesions was extremely higher with the addition of autofluorescence bronchoscopy than white light bronchoscopy alone, whereas there was no significant difference between autofluorescence bronchoscopy and white light bronchoscopy alone for the detection of non-malignant and malignant lesions. Autofluorescence bronchoscopy is a novel modality for the early detection of bronchial abnormality, especially for bronchial premalignant lesions.